Pet Imaging ct head scan or positron emission tomography is a diagnostic tool that produces images based on the detection of radiation from the emission of positrons. Positrons are tiny particles produced from a radioactive substance administered to the patient and absorbed in the body or specific area. The images of the body taken during this scanning process are used to evaluate a variety of diseases.

Your nurse or an x-ray technician will escort you into an exam room with the Pet scanner. The scanner itself is easily detectable it has a hole in the middle and looks like a large doughnut. Inside the Pet machine are multiple rings of detectors that record the emission of energy from the radioactive substance in your body, creating an image of a specific part of your body.

You will be asked to lie down on the exam table; an in IV will be started so that you can receive a radioactive substance called radiotracer. It will take approximately 30 to 60 minutes for the radiotracer to make its way through your body and be absorbed by the organ or tissue to be imaged. During that time, you'll rest quietly and avoid movement or talking, because this can alter the distribution of the substance. The radioactive substance in your body cannot be felt by you.

Once the radioactive substance has been absorbed, still lying on the exam table, you will be moved through the hole of the machine. The images are displayed on a monitor of a nearby computer. You will need to remain as still as possible during the exam, which takes about 30-45 minutes.